1,367 research outputs found
Target value design: using collaboration and a lean approach to reduce construction cost
Target Costing is an effective management technique that has been used in manufacturing for decades to achieve cost predictability during new products development. Adoption of this technique promises benefits for the construction industry as it struggles to raise the number of successful outcomes and certainty of project delivery in terms of cost, quality and time. Target Value Design is a management approach that takes the best features of Target Costing and adapts them to the peculiarities of construction. In this paper the concept of Target Value Design is introduced based on the results of action research carried out on 12 construction projects in the USA. It has been shown that systemic application of Target Value Design leads to significant improvement of project performance – the final cost of projects was on average 15% less than market cost. The construction industry already has approaches that have similarities with elements of the Target Value Design process or uses the same terminology, e.g. Partnering and Target Cost Contracts, Cost planning, etc. Following an exploration of the similarities and differences Target Value Design is positioned as a form of Target Costing for construction that offers a more reliable route to successful projects outcomes
The use of disjunct eddy sampling methods for the determination of ecosystem level fluxes of trace gases
The concept of disjunct eddy sampling (DES)
for use in measuring ecosystem-level micrometeorological
fluxes is re-examined. The governing equations are discussed
as well as other practical considerations and guidelines concerning
this sampling method as it is applied to either the
disjunct eddy covariance (DEC) or disjunct eddy accumulation
(DEA) techniques. A disjunct eddy sampling system
was constructed that could either be combined with relatively
slow sensors (response time of 2 to 40 s) to measure
fluxes using DEC, or could also be used to accumulate samples
in stable reservoirs for later laboratory analysis (DEA
technique). Both the DEC and DEA modes of this sampler
were tested against conventional eddy covariance (EC) for
fluxes of either CO2 (DEC) or isoprene (DEA). Good agreement
in both modes was observed relative to the EC systems.
However, the uncertainty in a single DEA flux measurement
was considerable (40%) due to both the reduced statistical
sampling and the analytical precision of the concentration
difference measurements. We have also re-investigated
the effects of nonzero mean vertical wind velocity on accumulation
techniques as it relates to our DEA measurements.
Despite the higher uncertainty, disjunct eddy sampling can
provide an alternative technique to eddy covariance for determining
ecosystem-level fluxes for species where fast sensors
do not currently exist
An O(N) symmetric extension of the Sine-Gordon Equation
We discuss an O(N) exension of the Sine-Gordon (S-G)equation which allows us
to perform an expansion around the leading order in large-N result using
Path-Integral methods. In leading order we show our methods agree with the
results of a variational calculation at large-N. We discuss the striking
differences for a non-polynomial interaction between the form for the effective
potential in the Gaussian approximation that one obtains at large-N when
compared to the N=1 case. This is in contrast to the case when the classical
potential is a polynomial in the field and no such drastic differences occur.
We find for our large-N extension of the Sine-Gordon model that the unbroken
ground state is unstable as one increases the coupling constant (as it is for
the original S-G equation) and we determine the stability criteria.Comment: 21 pages, Latex (Revtex4) v3:minor grammatical changes and addition
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